Devices are known that have the ability to brown an object by applying heat through the use of a heating element such as a resistive metal strip. FIG. 1 shows a prior art toaster 100 that is utilized for toasting a piece of bread. As shown, the toaster 100 utilizes a first heating element 110, and a second heating element (not shown) that are in close proximity to each other. The heating elements typically are wrapped around or backed by a heat resistant object 120, such as a mica sheet. The heating elements are connected to a power line 130 through a switch (not shown). In operation, a piece of bread is placed between the heating elements and the switch is closed for a period of time (t) until the bread is browned to a desired level. The surface of the bread after browning typically has a uniform monotonic browning pattern. An oven utilizes a similar arrangement of one or two heating elements to uniformly brown or dry objects placed therein such as food objects, pottery objects, industrial objects, etc.
In the prior art, it is also known that placing a heat resistant object between the heating element and the object to be browned, such as a slice of bread, may produce a non-uniform pattern of browning. Such systems are described in U.S. Pat. No. 1,892,117 to Perkins, U.S. Pat. No. 4,656,927 to Mosby, and U.S. Pat. No. 5,156,637 to Wai-Ching. The problem with these prior art toasters is that differently shaped heat resistant objects are required for producing each different heating pattern in the bread.
Japanese Patent No. 3,258,226 to Masaru shows a system wherein a changeable mold is utilized as the resistant object. In this system, a computer is connected to the toaster. The mold is transformed into the shape of characters shown on the computer display. The mold is then brought into contact with the surface of the bread and the toaster is then switched on. The portion of the bread surface in contact with the mold is not toasted and the other portions of the bread surface are toasted. In this way, desired characters may be freely drawn or patterns formed on a slice of bread. This system is very complex in that a changeable mold is required to form the desired patterns on the bread surface. This has the effect of raising the price and complexity of the toaster.
Japanese Patent No. 2,279,118 to Toshihiko shows a different type of toaster wherein a heater nozzle is utilized for drawing a pattern onto the surface of the bread. In operation, the heater nozzle is moved over the surface of the bread while air is blown through the heater nozzle. The air is heated by the heater nozzle and blown at the surface of the bread thereby producing a browning of the surface of the bread. The heater nozzle is controlled by a stepper motor connected to a control circuit for the purposes of moving the heater nozzle over the surface of the bread thereby forming a desired pattern on the surface of the bread. This toaster is again overly complex and expensive to implement and has the added drawback of overly drying the bread as the pattern is drawn.
Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art.
It is a further object of the present invention to provide an apparatus wherein a desired pattern may be readily browned into the surface of an object in a simple and inexpensive way.
It is still a further object of the present invention to provide an apparatus that may form a desired browning pattern without the need of utilizing changeable heat resistant shields.
A still yet further object of the present invention is to produce a heating apparatus wherein the shape/size of the heating pattern is controllable.